919 resultados para Historically Black Colleges and Universities


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The association between birthweight and blood pressure (BP), and birthweight and serum lipid concentrations at age 7 through 11 years was examined in 1446 black and white children. The prevalence ratio (with 95% confidence interval) for being in the race-, sex- and age-specific upper decile of diastolic BP in children born with low birthweight (LBW, $<$2500 grams) versus children with birthweight $\geq$2500 grams was for black boys, 2.66 (1.24-5.70). In the other race-sex groups for diastolic BP, and in all race-sex groups for systolic BP this ratio did not differ from one. Among white boys with LBW, but not in the other race-sex groups, higher than expected percentages of subjects were in the highest decile group of triglyceride concentrations (0.01 $<$ p $<$ 0.05). The prevalence ratio was 2.42 (1.19-4.91). When prematures were excluded only more than expected white girls with LBW were in the highest decile group of triglyceride concentrations. The prevalence ratio was 3.23 (1.16-9.00). Prevalence ratios for triglyceride concentrations in black boys and girls, and for LDL/HDL-C ratio, cholesterol and VLDL-C concentrations in all race-sex groups were not different from one in analyses including and in those excluding prematures. Mean triglyceride concentrations stratified by tertiles of Quetelet Index, race and sex showed a strongly positive association between triglyceride concentrations and Quetelet Index, and in the upper tertile of the Quetelet Index an association between LBW and raised triglyceride concentrations. Multiple linear regression analyses showed that after adjusting for sex, race and age present Quetelet Index (p $<$ 0.001) is a much stronger predictor of systolic and diastolic BP, and also of LDL-C/HDL-C ratio and triglyceride concentrations in this age group than birthweight (p $>$ 0.05). Thus, an association between LBW and subsequent risk for elevated BP was confirmed for diastolic BP in black boys, but not for the other race-sex groups, and not for systolic BP in any group. This is the first study finding an association between LBW and elevated triglyceride concentrations in boys (white and black) and girls (white). A follow-up study to assess whether the findings can be confirmed at adult age is recommended. ^

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Health care workers have been known to carry into the workplace a variety of judgmental and negative attitudes towards their patients. In no other area of patient care has this issue been more pronounced as in the management of patients with AIDS. Health care workers have refused to treat or manage patients with AIDS and have often treated them more harshly than identically described leukemia patients. Some health care institutions have simply refused to admit patients with AIDS and even recent applicants to medical colleges and schools of nursing have indicated a preference for schools in areas with low prevalence of HIV disease. Since the attitudes of health care workers do have significant consequences on patient management, this study was carried out to determine the differences in clinical practice in Nigeria and the United States of America as it relates to knowledge of a patient's HIV status, determine HIV prevalence and culture in each of the study sites and how they impact on infection control practices, determine the relationship between infection control practices and fear of AIDS, and also determine the predictors of safe infection control practices in each of the study sites.^ The study utilized the 38-item fear of AIDS scale and the measure of infection control questionnaire for its data. Questionnaires were administered to health care workers at the university teaching hospital sites of Houston, Texas and Calabar in Nigeria. Data was analyzed using a chi-square test, and where appropriate, a student t-tests to establish the demographic variables for each country. Factor analysis was done using principal components analysis followed by varimax rotation to simple structure. The subscale scores for each study site were compared using t-tests (separate variance estimates) and utilizing Bonferroni adjustments for number of tests. Finally, correlations were carried out between infection control procedures and fear of AIDS in each study site using Pearson-product moment correlation coefficients.^ The study revealed that there were five dimensions of the fear of AIDS in health care workers, namely fear of loss of control, fear of sex, fear of HIV infection through blood and illness, fear of death and medical interventions and fear of contact with out-groups. Fear of loss of control was the primary area of concern in the Nigerian health care workers whereas fear of HIV infection through blood and illness was the most important area of AIDS related feats in United States health care workers. The study also revealed that infection control precautions and practices in Nigeria were based more on normative and social pressures whereas it was based on knowledge of disease transmission, supervision and employee discipline in the United States, and thus stresses the need for focused educational programs in health care settings that emphasize universal precautions at all times and that are sensitive to the cultural nuances of that particular environment. ^

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Little is known about the etiology of colorectal adenomatous polyps, although they are generally considered to be precursor lesions to colorectal carcinoma. To investigate the associations of colorectal adenomatous polyps with dietary intake of calcium, total fat and fiber, a case comparison study was conducted among 98 persons who had first occurrences of adenomatous polyps and 408 persons who did not have colorectal polyps.^ The study population comprised Black, White and Hispanic males and females ages 35 to 80 inclusive, who underwent a sigmoidoscopy or total colonoscopy at collaborating clinics in the Texas Medical Center at Houston between September 1991 and November 1992, and met the eligibility criteria. Case participants were those who had a first-time diagnosis of adenomatous polyps. Comparison participants were individuals who underwent the same diagnostic procedure as the cases and met the same eligibility criteria but had no colorectal polyps. A food frequency questionnaire was administered by interview to obtain information about diet during the 28 days preceding the interview.^ Dietary intake of total fiber was inversely associated with risk of adenomatous polyps. An increment of 15 gm/day in energy-adjusted intake of fiber was associated with a relative odds of 0.39 with a 95% confidence interval of 0.20 to 0.79, after adjustment for age, sex, ethnicity, body mass index, cigarette smoking, family history of colorectal cancer and intake of nonsteroidal anti-inflammatory drugs. No association between dietary intake of total fat and risk of adenomatous polyps was observed. When total fat was analyzed as percent of energy, an increment of 15.3% in intake was associated with a relative odds of 0.98 with a 95% confidence interval of 0.53 to 1.80. However, few persons in the study group had intakes below 25% of energy from total fat. An inverse association was observed between energy-adjusted intake of dietary calcium and risk of adenomatous polyps, but this was not statistically significant; an increment of 638 mg/day was associated with a relative odds of 0.77 with a 95% confidence interval of 0.41 to 1.38. Intake of calcium did not appear to strongly modify the association between intake of fat and risk of adenomatous polyps, perhaps because the study group included few people with calcium intake below 400 mg/day.^ These results support the idea that dietary fiber decreases risk of adenomatous polyps. Further studies are needed on the association of dietary calcium and fat with risk of colorectal adenomatous polyps in populations where individuals vary widely in intake of these nutrients. ^

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For adolescents, unprotected sexual intercourse is the primary cause of sexually transmitted disease (STD), including Human Immunodeficiency Virus (HIV) infection (virus which causes Acquired Immunodeficiency Syndrome (AIDS)), and pregnancy. Although many studies on adolescent sexual behavior have addressed racial/ethnic differences, few studies have examined the relation between race/ethnicity while controlling for other sociocultural and psychosocial variables. The purpose of this study is to examine the relationship between racial/ethnic categories and selected sociocultural and psychosocial variables, with reported adolescent sexual risk-taking and preventive behavior.^ A self-administered questionnaire was used to collect information from 3132 students in a Texas school district (Section 3.5.2). The instrument contained approximately 100 questions on demographic characteristics, sexual behavior, and psychosocial determinants of sexual behavior. Based on the findings of this study, the following major conclusions are made: (1) There are differences in reported sexual risk-taking and preventive behavior among Black, Hispanic and White adolescents in this study. The stratified analysis by gender further suggests significant gender differences in reported sexual behavior among the three racial/ethnic groups. (2) Gender, living arrangement, academic grades, and language spoken at home modified the association between reported sexual risk-taking and preventive behavior and race/ethnicity in this study. This suggests that these sociocultural variables should be considered in future research and practice involving multicultural populations. (3) There are differences in selected psychosocial determinants among the three racial/ethnic groups and between males and females. These differences were consistent with the reported sexual risk-taking and preventive behaviors among race/ethnicity and gender for adolescents in this study. The findings support the consideration of psychosocial determinants in research and interventions addressing adolescent sexual behavior among different racial/ethnic groups.^ Based on the results of this study, two recommendations for practice are made. First, health professionals developing interventions for adolescents from different cultural backgrounds and gender need to be familiar with the specific sociocultural and psychosocial factors which will reduce risky sexual behavior, and promote protective behavior. Second, the need for immediate, realistic, and continuous HIV/STD and pregnancy prevention programs for children and adolescents should be considered. ^

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The dataset is based on samples collected in the summer of 2001 in the Western Black Sea in front of Bulgaria coast (transects at c. Kaliakra and c. Galata). The whole dataset is composed of 26 samples (from 10 stations of National Monitoring Grid) with data of mesozooplankton species composition abundance and biomass. Samples were collected in discrete layers 0-10, 10-20, 10-25, 25-50, 50-75, 75-90. Zooplankton samples were collected with vertical closing Juday net,diameter - 36cm, mesh size 150 µm. Tows were performed from surface down to bottom meters depths in discrete layers. Samples were preserved by a 4% formaldehyde sea water buffered solution. Sampling volume was estimated by multiplying the mouth area with the wire length. Mesozooplankton abundance: The collected material was analysed using the method of Domov (1959). Samples were brought to volume of 25-30 ml depending upon zooplankton density and mixed intensively until all organisms were distributed randomly in the sample volume. After that 5 ml of sample was taken and poured in the counting chamber which is a rectangle form for taxomomic identification and count. Large (> 1 mm body length) and not abundant species were calculated in whole sample. Counting and measuring of organisms were made in the Dimov chamber under the stereomicroscope to the lowest taxon possible. Taxonomic identification was done at the Institute of Oceanology by Lyudmila Kamburska and Kremena Stefanova using the relevant taxonomic literature (Mordukhay-Boltovskoy, F.D. (Ed.). 1968, 1969,1972). Taxon-specific abundance: The collected material was analysed using the method of Domov (1959). Samples were brought to volume of 25-30 ml depending upon zooplankton density and mixed intensively until all organisms were distributed randomly in the sample volume. After that 5 ml of sample was taken and poured in the counting chamber which is a rectangle form for taxomomic identification and count. Copepods and Cladoceras were identified and enumerated; the other mesozooplankters were identified and enumerated at higher taxonomic level (commonly named as mesozooplankton groups). Large (> 1 mm body length) and not abundant species were calculated in whole sample. Counting and measuring of organisms were made in the Dimov chamber under the stereomicroscope to the lowest taxon possible. Taxonomic identification was done at the Institute of Oceanology by Lyudmila Kamburska and Kremena Stefanova using the relevant taxonomic literature (Mordukhay-Boltovskoy, F.D. (Ed.). 1968, 1969,1972).

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Black shale samples of Jurassic to Cretaceous age recovered during the 'Norwegian Shelf Drilling Program' between 1987 and 1991 from Sites 7430/10-U-01 (Barents Sea), 6814/04-U-02 (Norwegian Shelf near the Lofoten) and 6307/07-U-02 (Norwegian Shelf near Trondheim) were analyzed for major and trace elements. These laminated black shales are characterized by high total organic carbon (TOC) and total sulfur (TS) contents as well as by significant enrichments in several redox-sensitive and/or sulfide-forming trace metals (Ag, Bi, Cd, Co, Cr, Cu, Mo, Ni, Re, Sb, Tl, U, V, and Zn). Enrichment factors relative to 'average shale' are comparable to those found in Cenomanian-Turonian boundary event (CTBE) black shales and Mediterranean sapropels. The Re content is high in the studied black shales, with maximum values up to 1221 ng/g. Re/Mo ratios averaging 2.3*10**-3 are close to the seawater value. High trace metal enrichments and Re/Mo ratios close to the seawater value point to a dominantly anoxic and sulfidic water column during black shale formation. Interbeds with higher Re/Mo ratios, especially in high-resolution sampled core sections, point to brief periods of suboxic conditions. Additionally, enhanced Zn concentrations in the black shales from the Barents Sea support the assumption that hydrothermal activity was also high during black shale deposition. Trace metal signatures of black shales at different drill sites on a transect along the Norwegian Shelf are not only influenced by water depth but also by their location in the boreal realm. Metal enrichments are higher in the northern compared to the southern sites. Volgian (=Tithonian 151-144 Ma BP) black shales exhibit elevated trace metal contents in comparison to their Berriasian (144-137 Ma BP) counterparts. This probably reflects a change in the circulation pattern during periods of black shale formation. Therefore different paleoceanographic conditions, probably controlled by climatic change linked to the transgression of the paleo-sealevel and the North Atlantic opening, may have developed from the Volgian to the Berriasian.

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Profiles of Mo/total organic carbon (TOC) through the Lower Toarcian black shales of the Cleveland Basin, Yorkshire, United Kingdom, and the Posidonia shale of Germany and Switzerland reveal water mass restriction during the interval from late tenuicostatum Zone times to early bifrons Zone times, times which include that of the putative Early Toarcian oceanic anoxic event. The degree of restriction is revealed by crossplots of Mo and TOC concentrations for the Cleveland Basin, which define two linear arrays with regression slopes (ppm/%) of 0.5 and 17. The slope of 0.5 applies to sediment from the upper semicelatum and exaratum Subzones. This value, which is one tenth of that for modern sediments from the Black Sea (Mo/TOC regression slope 4.5), reveals that water mass restriction during this interval was around 10 times more severe than in the modern Black Sea; the renewal frequency of the water mass was between 4 and 40 ka. The Mo/TOC regression slope of 17 applies to the overlying falciferum and commune subzones: the value shows that restriction in this interval was less severe and that the renewal frequency of the water mass was between 10 and 130 years. The more restricted of the two intervals has been termed the Early Toarcian oceanic anoxic event but is shown to be an event caused by basin restriction local to NW Europe. Crossplots of Re, Os, and Mo against TOC show similar trends of increasing element concentration with increase in TOC but with differing slopes. Together with modeling of 187Os/188Os and d98Mo, the element/TOC trends show that drawdown of Re, Os, and Mo was essentially complete during upper semicelatum and exaratum Subzone times (Mo/TOC regression slope of 0.5). Drawdown sensitized the restricted water mass to isotopic change forced by freshwater mixing so that continental inputs of Re, Os, and Mo, via a low-salinity surface layer, created isotopic excursions of up to 1.3 per mil in d98Mo and up to 0.6 per mil for 187Os/188Os. Restriction thereby compromises attempts to date Toarcian black shales, and possibly all black shales, using Re-Os chronology and introduces a confounding influence in the attempts to use d98Mo and initial 187Os/188Os for palaeo-oceanographic interpretation.

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Drilling at Site 534 in the Blake-Bahama Basin recovered 268 m of Lower Cretaceous, Berriasian to Hauterivian, pelagic carbonates, together with volumetrically minor intercalations of claystone, black shales, and terrigenous and calcareous elastics. Radiolarian nannofossil pelagic carbonates accumulated in water depths of about 3300 to 3650 m, below the ACD (aragonite compensation depth) but close to the CCD (calcite compensation depth). Radiolarian abundance points to a relatively fertile ocean. In the Hauterivian and Barremian, during times of warm, humid climate and rising sea level, turbiditic influxes of both terrigenous and calcareous sediments, and minor debris flows were derived from the adjacent Blake Plateau. The claystones and black shales accumulated on the continental rise, then were redeposited onto the abyssal plain by turbidity currents. Dark organic-rich and pale organic-poor couplets are attributed to climatic variations on land, which controlled the input of terrigenous organic matter. Highly persistent, fine, parallel lamination in the pelagic chalks is explained by repeated algal "blooms." During early diagenesis, organic-poor carbonates remained oxygenated and were cemented early, whereas organic-rich intervals, devoid of burrowing organisms, continued to compact later in diagenesis. Interstitial dissolved-oxygen levels fluctuated repeatedly, but bottom waters were never static nor anoxic. The central western Atlantic in the Lower Cretaceous was thus a relatively fertile and wellmixed ocean basin.

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Low-molecular-weight (LMW) alcohols are produced during the microbial degradation of organic matter from precursors such as lignin, pectin, and carbohydrates. The biogeochemical behavior of these alcohols in marine sediment is poorly constrained but potentially central to carbon cycling. Little is known about LMW alcohols in sediment pore waters because of their low concentrations and high water miscibility, both of which pose substantial analytical challenges. In this study, three alternative methods were adapted for the analysis of trace amounts of methanol and ethanol in small volumes of saline pore waters: direct aqueous injection (DAI), solid-phase microextraction (SPME), and purge and trap (P&T) in combination with gas chromatography (GC) coupled to either a flame ionization detector (FID) or a mass spectrometer (MS). Key modifications included the desalination of samples prior to DAI, the use of a threaded midget bubbler to purge small-volume samples under heated conditions and the addition of salt during P&T. All three methods were validated for LMW alcohol analysis, and the lowest detection limit (60 nM and 40 nM for methanol and ethanol, respectively) was achieved with the P&T technique. With these methods, ambient concentrations of volatile alcohols were determined for the first time in marine sediment pore waters of the Black Sea and the Gulf of Mexico. A strong correlation between the two compounds was observed and tentatively interpreted as being controlled by similar sources and sinks at the examined stations.

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The dataset is based on samples collected in the summer of 2002 in the Western Black Sea in front of Bulgaria coast. The whole dataset is composed of 47 samples (from 19 stations of National Monitoring Grid) with data of mesozooplankton species composition abundance and biomass. Sampling for zooplankton was performed from bottom up to the surface at depths depending on water column stratification and the thermocline depth. Zooplankton samples were collected with vertical closing Juday net,diameter - 36cm, mesh size 150 µm. Tows were performed from surface down to bottom meters depths in discrete layers. Samples were preserved by a 4% formaldehyde sea water buffered solution. Sampling volume was estimated by multiplying the mouth area with the wire length. Mesozooplankton abundance: The collected material was analysed using the method of Domov (1959). Samples were brought to volume of 25-30 ml depending upon zooplankton density and mixed intensively until all organisms were distributed randomly in the sample volume. After that 5 ml of sample was taken and poured in the counting chamber which is a rectangle form for taxomomic identification and count. Large (> 1 mm body length) and not abundant species were calculated in whole sample. Counting and measuring of organisms were made in the Dimov chamber under the stereomicroscope to the lowest taxon possible. Taxonomic identification was done at the Institute of Oceanology by Lyudmila Kamburska using the relevant taxonomic literature (Mordukhay-Boltovskoy, F.D. (Ed.). 1968, 1969,1972). Taxon-specific abundance: The collected material was analysed using the method of Domov (1959). Samples were brought to volume of 25-30 ml depending upon zooplankton density and mixed intensively until all organisms were distributed randomly in the sample volume. After that 5 ml of sample was taken and poured in the counting chamber which is a rectangle form for taxomomic identification and count. Copepods and Cladoceras were identified and enumerated; the other mesozooplankters were identified and enumerated at higher taxonomic level (commonly named as mesozooplankton groups). Large (> 1 mm body length) and not abundant species were calculated in whole sample. Counting and measuring of organisms were made in the Dimov chamber under the stereomicroscope to the lowest taxon possible. Taxonomic identification was done at the Institute of Oceanology by Lyudmila Kamburska using the relevant taxonomic literature (Mordukhay-Boltovskoy, F.D. (Ed.). 1968, 1969,1972).

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Organic-carbon-rich 'black shales' and adjacent organic-carbon-poor rocks from three different Cretaceous settings encountered during ODP Leg 103 have been studied by organic geochemical methods. Rock-Eval analysis, carbon isotope data, and lipid biomarkers show organic matter to contain varying proportions of marine and continental materials. In Hauterivian-Barremian organic-carbon-rich marlstone turbidites, large amounts of land-derived organic matter are found. Aptian-Albian black-colored shales are interspersed within green claystones, from which they differ by containing more marine organic matter. An abbreviated layer of black shale from the Cenomanian/Turonian boundary is dominated by well-preserved marine organic matter. Downslope transport and rapid reburial within a predominantly oxygenated deep-water setting created most of these examples of black shales, except for the Cenomanian-Turonian deposits in which deep-water anoxia may have been involved.

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Organic matter contents of black shales from the Cretaceous Hatteras and Blake-Bahama formations have been compared to those from surrounding organic-poor strata using C/N ratios, d13C values, and distributions of extractable and nonsolvent-extractable, long-chain hydrocarbons, acids, and alcohols. The proportion of marine and land-derived organic matter varies considerably among all samples, although terrigenous components generally dominate. Most black shales are hydrocarbon-poor relative to their organic-carbon concentrations. Deposition of the black shales in Hole 603B evidently occurred through turbiditic relocation from shallower landward sites and rapid reburial at this outer continental rise location under generally oxygenated bottom-water conditions.

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A most significant finding of the ODP Leg 107 drilling campaign was the recovery of at least 56 distinct sapropel intervals in upper Pliocene to Pleistocene sediments of six sites drilled in the Tyrrhenian Sea. Except for 3 repots of disturbed organic-rich sediments - recovered in Core 201 of the Swedish Deep-Sea Expedition, in Core 2R-1,107 cm of Site 373 (Leg 13 DSDP) and at Site 373, Core 1-2,O-5 cm of DSDP Leg 42A - sapropels had previously only been described from the eastern Mediterranean and the Black Sea. Scientific deep-sea drilling in the Tyrrhenian Sea during DSDP Legs 13 and 42A apparently missed most of these deposits due to spot coring and rotary drilling techniques; high sedimentation rates may have precluded recovery by conventional gravity coring devices. The recovery of multiple layers of sapropels and sapropelic sediments in the Tyrrhenian Sea demonstrates that oceanographic conditions conducive to sapropel formation were not confined to the Black Sea and eastern Mediterranean, but occurred sporadically and possibly simultaneously in the entire Mediterranean during the Pliocene and Pleistocene. In the light of this finding, previous models of sapropel genesis may need reconsideration. In this paper, we present some initial data on the Tyrrhenian sapropels and suggest some implications of their massive occurrence in the western Mediterranean realm. We end by outlining possible causes for deposition of sapropels in an attempt to revive the interest in sapropels and their paleoceanographic significance.